This is a roundup of all the best science software for Windows. All of the science software are free to download, and released under an open source license.

Graphical Interfaces for R - The R language (and open-source software) is the de facto standard among statisticians for the development of statistical software, and is widely used for statistical software development and data analysis.
Chemistry - Chemistry is the study of matter and the changes it undergoes. It is an extremely vivacious science which deals with a molecular scale and atomic interpretation of the world we live in, helping us to understand that world. Chemistry is regarded as the central science, given its close links with physics and engineering, with biology and medicine, and with geology and earth science.
Physics - Physics is a natural science concerned with the study of matter and energy applying laws that govern natural phenomena. It encompasses the study of the universe from the largest galaxies to subatomic particles, covering mechanics, radiation, heat, electricity, sound, magnetism and the structure of atoms.
Biology - Biology is a natural science concerned with the study of living things, ranging from microscopic organisms up to the largest known animal, the blue whale.
Bioinformatics - Bioinformatics has been defined in many different ways, but it is common ground to regard this discipline as the application of mathematics, computing and statistics to the analysis of biological information.
Astronomy - Astronomy is a branch of science that deals with the study of celestial objects (including stars, planets, moons, comets, asteroids, meteor showers, nebulae, star clusters and galaxies) and other phenomena.
GPS - The Global Positioning System (GPS) is a satellite-based navigation satellite system consisting of a network of satellites which provide positioning, navigation, and timing services in all weather, anywhere on or near the Earth.
Robotics - Robotics is the branch of artificial intelligence concerned with the study of robots, automatically guided machines which are able to carry out tasks and functions on their own. Robotics covers a wide spectrum of areas including the design, construction, operation and manufacture of robots.
Earth science - Earth science (also known as geoscience) is the focus of understanding the sciences related to the planet Earth. It includes a wide range of fields such as geology, geography, geophysics, meteorology, oceanography, and glaciology.
Geometry - Geometry software covers a wide range of application areas, including pure Euclidean and non-Euclidean geometry, computer-aided design, and computational kinematics. It is often found being used for learning and teaching mathematics in schools and colleges and for research purposes.